Michigan gas prices have increased by about 7 cents on average over the past week. AAA of Michigan says the average price of a gallon of regular unleaded is $2.07 a gallon. The cheapest fuel can be found in Traverse City and Flint, where some pumps are below the $2-dollar mark. The most expensive gas is once again in the central an western UP, with pumps as high as $2.20 a gallon. Port Huron area pumps are asking approximately $2.03 a gallon.